Helianthoides, commonly crawl inn as sunflower starfish, begin their life story cycle when both(prenominal) male and females release their nut cases or sperm openly into the ocean waters [a]. The starfish know when to release their sperm and egg because of an internal calendar. This makes sure both parties have a simultaneous release time, to increase fertilisation. It is hence required that the egg and sperm meet and fuse to pattern a fertilized egg [b]. The unexampledly fertilized egg then divides into 2 equal cells [c] then into four [d] and remains dividing until a take blastula has been formed [e]. This blastula is ciliated and hatches out of the fertilization membrane. After the first day has passed we ar left wing with a gastrula [f]. This is a two layered stratum with an inner entoblast and an outer ectoderm. Since the blastula [e] stage, an indentation has been produced in the gastrula [f]. This bequeath shed rise to the future digestive system. succeeding(prenominal) the top of this in the buff pore protrudes wider [g]. The wider portion then is pinched off and forms the coelomic sacs [h]. (The coelomic sacs will riper become the water vascular system). Next through advancing maturity, an early bipinnaria or early larva is formed [i]. because several portions of the early larva elongate and separate, this results in a bipinnaria [j], which swims and feeds in plankton. The bipinnaria advances further through the stages of early brachiolaria [k] and late brachiolaria [l]. Within the late brachiolaria there is a small portion called the adult rudiment. Next the late brachiolaria undergoes some(prenominal) changes in which it looses many parts and changes many existing parts in order to become a setting larva [m]. During this stage it usually clings onto rocks and such. The setting larva then undergoes metabolic process [see notes] where many things occur such as the old brim being closed off and a new maven made. Also the old anus is cut off and a new champion protrudes. After these changes and many more we be left with an early starfish [n].
The early starfish grows tube feet and is in the end able to crawl and it resembles a mature starfish. At this stage we are dealing with a Juvenile Starfish [o]. As this matures we at last have an adult starfish [p] which one day will release sperm or egg and start the life cycle over again.
Notes: o         metamorphosis is the term used to describe a form of maturement from egg to adult in which there is a serial publication of distinct stages, or change of habitat.
o         Some starfish have over 50 legs.
o         Starfish are echinoderms and breathe through their skin.
o         Some sunflower starfish grow to be over five and a fractional feet across.
o         There are more than 1,800 types of starfish.
o         They are most commonly found between Alaska and the Puget Sound.
by.... B. anderson
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